Infusion pump devices and systems are relatively well known in the medical arts, for use in delivering or dispensing an agent, such as insulin or another prescribed medication, to a patient. A typical infusion pump includes a pump drive system which typically includes a small motor and drive train components that convert rotational motor motion to a translational displacement of a plunger (or stopper) in a reservoir that delivers medication from the reservoir to the body of a user via a fluid path created between the reservoir and the body of a user. Use of infusion pump therapy has been increasing, especially for delivering insulin for diabetics.
Continuous insulin infusion provides greater control of a diabetic's condition, and hence, control schemes are being developed that allow insulin infusion pumps to monitor and regulate a user's blood glucose level in a substantially continuous and autonomous manner, for example, overnight while the user is sleeping. Regulating blood glucose level is complicated by variations in the response time for the type of insulin being used along with each user's individual insulin response. Predictive algorithms may be utilized to provide estimations of the future blood glucose levels as an aid in regulating the blood glucose level. Rather than continuously sampling and monitoring a user's blood glucose level, which may compromise battery life, intermittently obtained blood glucose data samples may be utilized for determining estimations of future blood glucose levels.
Problems arise, however, when one or more blood glucose data samples intended for input to a predictive algorithm are corrupted, lost, or otherwise invalid, for example, due to noise, transmission errors, or the like. For example, in the case of recursive prediction algorithms, the prediction algorithm may be reset to eliminate the so-called “bad” data from undesirably influencing the device operation. Such an approach also incurs the lag time required for the prediction algorithm to achieve a desired level of reliability, and thus, would result in an inability to provide predictive control for periods of time.